Smart cards are personalized security devices, defined by the ISO 7816 standard and its derivatives, as published by the International Standards Organization. A smart card may have a form factor of a credit card and may include a semiconductor device. The semiconductor device may include a memory that can be programmed with security information (e.g. a private decryption key, a private signing key, biometrics, an authentication certificate, etc.), and may include a decryption engine, e.g. a processor and/or dedicated logic, for example, dedicated decryption logic and/or dedicated signing logic. A smart card may include a connector for powering the semiconductor device and performing serial communication with an external device. A smart card may be used for visual identification, time cards, door access, and the like.
Part 3 of the ISO 7816 describes electronic signals and transmission protocols for smart cards. In this part of the standard, the format for an Answer to Reset (ATR) is defined. Every smart card is required to give an answer when it is reset by a smart card reader. A reset occurs when the smart card is powered up by a reader, usually when the smart card is inserted; however, the smart card reader has the capability to cause a smart card reset at any time. The ATR contains information about the smart card's capabilities, such as the bit rates that it can support, enabling the smart card reader to communicate further with the smart card. In addition, it may also contain information about the smart card manufacturer, and other hardware characteristics of the integrated circuit or the memory on the smart card.
A smart card reader may communicate with a computing device, such as a personal computer (PC) or a mobile communications device, to provide authentication for an intended user of the computing device. The user inserts his or her smart card into the smart card reader, and enters a secret, for example a personal identification number (PIN), to verify that he or she is the owner of the smart card. Once verified as a legitimate user, the PC will allow the user to log onto their account. The smart card may then be used to decrypt received messages, or to attach a digital signature to a message sent from the computing device. The smart card may also be used for user authentication, to verify a signature, and to encrypt outgoing messages. To use the smart card for such tasks, the computing device communicates instructions to the smart card reader, which the smart card reader then communicates to the smart card. The smart card reader waits for the smart card's response to each instruction, and then communicates these responses back to the computing device. However, before any communications between the computing device and the smart card can begin, the smart card driver on the computing device requires information about the communication protocols and data transmission rates that are supported by the smart card. To obtain this information, the smart card driver on the computing device will usually send a request for the ATR to the smart card reader at the start of a communication session with the smart card.
If sent over a direct or wired connection, a request for ATR and the returned ATR may be transmitted very efficiently. The smart card reader and smart card are able to communicate when in direct physical contact with each other—the smart card has contacts and the smart card reader has a connector. Alternatively, for contactless smart cards, the smart card reader and the smart card are able to communicate when proximate using radio frequency signals. Depending on the design and implementation, the smart card reader and the computing device are able to communicate via a serial port, parallel port, universal serial bus (USB) port, or other direct or wired link.
Smart card readers may communicate with a computing device either via a wired connection, or via a wireless communication link. Wireless communication links are much slower than wired communication links. Yet wireless devices and wireless communications are increasingly replacing wired or direct communication links to allow more flexibility in device design and use. For example, Bluetooth® wireless technology provides an easy way for a wide range of Bluetooth® devices (BT devices) to communicate with each other and connect to the Internet without the need for wires, cables and connectors. Other wireless communication protocols include ZigBee™, radio frequency identification (RFID), ultra wideband (UWB), IEEE 802.11 and various proprietary wireless communication protocols.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity.